Marine Le Pen visited Trump Tower during an unannounced visit to New York yesterday.
The far-right French Front National leader has consistently praised Donald Trump and is currently in New York just four months before the French presidential elections, in which she has emerged as a frontrunner.
Ms Le Pen was spotted by journalists at Mr Trump's headquarters but it remains unclear whether she met with the businessman or his advisers.
A Trump aide had earlier told Bloomberg the president-elect had no plans to meet her.
Pictures published on social media showed Ms Le Pen holding a meeting with three men in what appeared to be a public area of the building.
The French politician's chief of staff was quoted as saying the trip to New York was a "private visit" and would only reveal that a meeting with Mr Trump was "not on her public agenda".
Ms Le Pen refused to confirm to journalists at Trump Tower whether or not she was meeting the president-elect.
She has previously called Mr Trump's election "a sign of hope" and said the Republican was "putting in place measures I have been demanding for years".
Speaking to CNN late last year, she said: "Donald Trump has made possible what was presented as completely impossible.
"So it's a sign of hope for those who cannot bear wild globalisation.
"They cannot bear the political life led by the elites."
Ms Le Pen is currently narrowly ahead in opinion polls for the first round of voting in France's presidential election.
The latest poll, published yesterday, gave her a 1.5pc lead over Republican candidate François Fillon.